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Home : Media : News
NEWS | April 11, 2024

NAVSEA Remembers Crew of USS Thresher

By Team Submarine Public Affairs

Naval Sea Systems Command (NAVSEA) hosted a Apr. 10 ceremony honoring 129 crewmembers — 16 officers, 96 enlisted Sailors, and 17 civilian technicians — who lost their lives onboard USS Thresher (SSN 593) 61 years prior.

NAVSEA staff reflected on the tragedy as well as programs and procedures since established to prevent future casualty.

Built to hunt and destroy hostile enemy submarines, Thresher was the world’s most technologically advanced nuclear-powered submarine of its time equipped with the most advanced weapons and detection systems available.

On April 9, 1963, Thresher, the lead nuclear-powered attack submarine of her class, sailed from Kittery, Maine, to approximately 220 miles east of Massachusetts to conduct deep-diving tests. After a rendezvous with Penguin-class submarine rescue ship USS Skylark (ASR 20), Thresher conducted trials throughout the day, before submerging overnight. The following morning, after reestablishing comms with Skylark, Thresher commenced deep-dive trials.

She dove slowly in a circular pattern beneath Skylark, maintaining communications, and stopping every 100 feet to check system integrity. But as Thresher approached her test depth, Skylark received an alarming, partial message. “ … Minor difficulties. Have positive up-angle. Attempting to blow …” Another unclear communique was received which included the number “900.”

No other messages were transmitted. The Navy would eventually establish that Thresher and its crew were lost once the boat descended below crush depth, due to uncontrolled flooding, and imploded under the devastating pressures of the ocean.

Keynote speaker, Mr. Robert Koonce, founder and president of High Reliability Group reflected on the crew lost and spoke on the importance of maintaining and promoting high standards of safety processes as well as accountability within the submarine community to prevent future casualties.

“There is nothing routine on a submarine,” said Koonce. “You cannot get complacent; you cannot let your guard down.”

A legacy of Thresher and its crew is the U.S. Navy’s Submarine Safety (SUBSAFE) program, launched in June 1963. SUBSAFE is a quality assurance program designed to maintain the safety of the submarine fleet, specifically, to provide maximum reasonable assurance that submarine hulls will stay watertight, and that they can recover from unanticipated flooding.

“The SUBSAFE program grew from this tragedy and now, it is a world-renowned safety organization,” said Ms. Stefanie Link, executive director for Program Executive Office Attack Submarines. “This is the case because we do not allow ignorance, arrogance, complacency, and denial within our ranks.”

SUBSAFE certification occurs throughout the areas of design, material, fabrication, and testing. Each step requires records collection, review, and approval. The records must also be stored for the entire life of the submarine. Material traceability starts at original manufacturing and continues up to the point of installation and through final certification. This tracking is so thorough that it includes records of source materials (such as which quarry a metal was mined from) and material manipulation processes (such as smelting).

Since the launch of the program, no SUBSAFE-certified submarine has been lost at sea.

Annual remembrance ceremonies keep the memory of the Thresher and its crew alive and serve as an opportunity to re-emphasize safety as a priority within NAVSEA.

The SUBSAFE program, an activity within Naval Sea Systems Command (NAVSEA) serves as a standard other government agencies emulate. Following the loss of the Space Shuttle, Columbia, the Columbia Accident Investigation Board identified SUBSAFE as one of only three "successful safety programs and practices that could be models for NASA." Several subject-matter expert exchanges were held to help NASA identify ways their program could be improved to prevent future catastrophic casualties.

“Our challenge today, 61 years after the loss of USS Thresher, is to maintain our vigilance, intensity, and integrity in all matters involving the SUBSAFE program to ensure adherence to the requirements, uphold the standards of the program, and keep our Sailors, shipmates, sisters and brothers, and now our children serving onboard submarines safe from the relentless and unforgiving sea,” said Link. “The supreme sacrifice of those lost on USS Thresher can best be remembered by never letting it happen again.”

For more information on the design, requirements, procurement, and construction of Navy submarines visit:

Team Submarines (